The autoimmune condition, Celiac disease, afflicts roughly
one in 133 Americans. It is caused by a combination of genetic and
environmental factors. Now a team of investigators from Spain shows
that the level of genetic risk of celiac disease influences the composition of
infants’ gut microbiota, and confirms earlier studies showing that the type of
milk feeding—breast vs. formula—also influences the species distribution. Their
hypothesis is that these changes in the intestinal microbiota may directly
influence the risk of celiac disease, and that if this is so, changes in
diet—particularly breast feeding—could reduce that risk. The research is
published in the August Applied and
Environmental Microbiology.

The newborn intestine is colonized immediately after birth
by microorganisms from the mother and the environment. Earlier research had
shown that breast feeding protects against celiac disease as compared to
formula feeding, as well as that the intestinal microbiota is less diverse in
breast- than in formula-fed infants, with different genera predominating in
each. The new research also shows that infants at high genetic risk of celiac
disease have a high prevalence of certain Bacteroides
spp that is different from the population in those at low genetic risk.

The investigators report further that the type of milk
influences Bacteroides species
composition, in particular with breast feeding favoring the prevalence of B. uniformis, a species associated with
the low risk genotype, and reducing differences in Bacteroides species
composition between the two genetic risk groups. “Altogether, this could
explain the protective role that breast-feeding plays against development of
celiac disease, as reported in previous observational studies,” says principal
investigator Yolanda Sanz of the Instituto de Agroquimica y Tecnologia
de Alimentos, Valencia,
Spain.

If associations between the composition of the gut
microbiota, the genotype, and incidence of celiac disease are confirmed, “We
will be able to recommend breastfeeding, and propose dietary intervention
trials to modulate the intestinal microbiota in subjects at risk of developing
celiac disease, in order to try to prevent its development,” says Sanz.

The study includes 75 full term infants, all with at least
one first degree relative suffering from celiac disease, but who had varying
degrees of genetic risk. In the study, the researchers sorted the infants into
two groups according to genetic risk, a high-risk (7-28 percent) group, and a
low-risk (less than one percent) group. They plan to follow the infants long
enough to determine who gets the disease, which will shed further light on
whether the intestinal flora influence risk.